Among the victims of floods, earthquakes, and hurricanes, there is an increased prevalence of post-traumatic stress disorder and depression, which are risk factors for suicidal thinking. We conducted this study to determine whether natural disasters affect suicide rates.From a list of all the events declared by the U.S. government to be federal disasters between 1982 and 1989, we selected the 377 counties that had each been affected by a single natural disaster during that period. We collected data on suicides during the 36 months before and the 48 months after the disaster and aligned the data around the month of the disaster. Pooled rates were calculated according to the type of disaster. Comparisons were made between the suicide rates before and those after disasters in the affected counties and in the entire United States.Suicide rates increased in the four years after floods by 13.8 percent, from 12.1 to 13.8 per 100,000 (P<0.001), in the two years after hurricanes by 31.0 percent, from 12.0 to 15.7 per 100,000 (P<0.001), and in the first year after earthquakes by 62.9 percent, from 19.2 to 31.3 per 100,000 (P<0.001). The four-year increase of 19.7 percent after earthquakes was not statistically significant. Rates computed in a similar manner for the entire United States were stable. The increases in suicide rates were found for both sexes and for all age groups. The suicide rates did not change significantly after tornadoes or severe storms.Our study shows that suicide rates increase after severe earthquakes, floods, and hurricanes and confirms the need for mental health support after severe disasters.